In order to configure a NAD located at the network end-user (or customer) premises to recognize at least one VC address (comprising a Virtual Path Indicator and Virtual Channel Indicator or VPI/VCI) to be used for traffic between the NAD and a remote NAC across an ATM link, it is currently necessary to obtain the list of VPI/VCI addresses corresponding to active VC's from the system administrator of the remote NAC. These VPI/VCI addresses are then either installed in the NAD during its manufacture or are specified by the end user using a configuration interface for the NAD once at the customer premises.
Most customers do not need to be aware of what VC's are being used by their NAD and therefore, do not wish to be directly involved in the configuration of the said NAD. These customers would prefer plug-and-play convenience “out of the box”.
Furthermore, with most Incumbent Local Exchange Carriers (ILEC's) currently providing ATM-enabled point-to-point Digital Subscriber Line (xDSL) services, VC's tend to be ‘hardcoded’ to a single set of VC addresses on a per ILEC basis. This hardcoding occurs at both the ILEC's DSL Access Multiplexor (DSLAM, or NAC, typically located at an ILEC's Central Office, or CO) and the Customer Premises (NAD) ends of an Asymmetric-DSL (ADSL) connection. With the entry of Competitive Local Exchange Carriers (CLEC's) in the Central Offices, it is foreseen that more sophisticated ATM VC management practices will be necessary. Specifically, VC addresses will not remain statically global to an entire ILEC or CLEC's xDSL user community.
Given that the 8-bit VPI and 16-bit VCI portions of a VC's address allow for over 16 million possibilities, it is not possible to test all 16 million possibilities within a reasonable time frame, a strategy designed to cover the most likely VPI/VCI possibilities in a minimal amount of time is necessary.
It is known that DSLAM vendors tend to limit their supported VC addresses to a specific range in order to reduce the amount of memory resources needed. For example, Alcatel limits the VPI range from 0 to 15, and the VCI range from 0 to 1023.
Therefore, there is a need to provide a configuration scheme which will allow the automatic detection of supported VC addresses on an ATM link between a local NAD and a remote NAC located at the network service provider in a minimal amount of time.